Method for manufacturing workpieces and apparatus

ABSTRACT

For vacuum treatment of workpieces by a multitude of distinct processing stations (P 11 -P 1n , P 21 -P 2m ) the processing stations are grouped in two groups (I and II). The workpieces are handled towards and from the processing stations of the first group (I) simultaneously, whereat the workpieces are treated by the processing stations of the second group (II) in a selectable individual sequence.

The present invention is directed to manufacturing of workpieces treatedby a multitude of vacuum treatment processes, thereby especially tomanufacturing of substrates like wafers, data storage disks orsubstrates for photovoltaic applications as for solar panelmanufacturing e.g. coated glass substrates.

For the treatment of substrates in vacuum e.g. coating with a multitudeof layers, heating, cooling, cleaning and etching, there exist a numberof principles to transport the substrates through the assembly ofevacuated processing stations without breaking the vacuum.

The US 2006/0054495 and the U.S. Pat. No. 5,658,114 show linearassemblies of vacuum processing stations. In the U.S. Pat. No. 5,655,277vacuum processing stations are assembled in a circular configuration.

In both cases, i.e. linear and circular arrangements, one cycle of theoverall processing can be subdivided in two types of steps, namelytransporting steps and processing steps. Typically, all the substrateswithin the processing apparatus are transported simultaneously, i.e.parallel in time, from one processing station to the next one. Thesubstrates are thereby passing all the stations in a well-definedsequence which is the same for all substrates being processed. Thetransport steps are followed by respective process steps, where thesubstrates are treated simultaneously by the vacuum processes in therespective vacuum processing stations.

A transport step of the substrates can only be started after all theprocesses in the respective vacuum process stations are completed. Thus,tact time of the overall apparatus is governed by the longest one of theprocessing time spans at the respective vacuum processing stations.

Such transport and processing in a parallel manner, i.e. simultaneouslyfor substrates involved, is favorable for achieving a high throughput(number of treated substrates per time unit) if the processing timespans in the respective vacuum treatment stations do not differ too muchfrom each other. The transport arrangement for serving the vacuumprocessing stations as well as the time control of such transportarrangement may be kept simple and thus the addressed processingprinciple is highly cost-efficient for manufacturing the addressedworkpieces.

On the other hand it is an inherent disadvantage of this concept thatthe longest processing time span determines the overall cycle time ofthe apparatus. Especially in cases, where one of the individualprocesses takes substantially longer than the other processes, theaddressed concept is inefficient due to the fact that the processingstations for the shorter processing time spans are used only duringfraction of time of the overall cycle time, i.e. high dead times occur.Shorter processing time spans can not be exploited, due to blocking ofthe overall cycle time of the apparatus by longer processing time spans.

In some cases this problem may be overcome by using two or moreidentical vacuum processing stations consecutively to subdivide theprocessing time spans of those processings with longer processing timespans. It is, as an example, possible to deposit certain layers in twoor more than two steps using a respective number of vacuum processingstations so as to adapt deposition time to shorter processing time spansin other processing stations. A longer processing time span for oneprocessing is subdivided into multiple processing time spans withrespective processings realized at subsequent processing stations.Thereby, the dead time of the overall apparatus can be minimized.

However, splitting of an individual process is not possible in allcases. As an example, deposition of very sensitive layers must beperformed uninterruptedly in one and the same processing station.

Another basic approach to the problem as mentioned above is, accordingto a second principle, to serve by a transport arrangement processingstations individually. Loading workpieces as of substrates into aprocessing station and removing them therefrom is established in asequential manner and processing the workpieces in the respectiveprocessing station is performed at least overlappingly in time and thussubstantially simultaneously, i.e. in parallel. After one individualprocessing has finished, transport to a next processing is accomplished.By this principle, dead time as mentioned above can be minimized. TheU.S. Pat. No. 4,715,921 shows an apparatus and processing according tothe principle as just addressed. It is known as “cluster” arrangementhaving a circular arrangement of individual processing stations groupedaround a central transport or handling chamber. By means of load/unloadlock stations vacuum environment may be upheld in the central transportchamber.

According to the U.S. Pat. No. 5,090,900 a central evacuatable transportchamber is connected to a plurality of processing stations. In this casethe substrates are transported sequentially and the overall systemoffers a high flexibility with respect to loading/unloading time of theindividual process stations. However, the facts that one centraltransport arrangement has to perform all the movements and only oneworkpiece can be handled at a time result in that such system is notoptimized for high throughput applications. Especially for a high numberof different processing stations the handling, i.e. transport activity,becomes the bottleneck for system throughput.

Thus, both basic principles which may be abbreviated as “simultaneoustransport” and “individual transport” have advantages and disadvantagesas addressed above. Both principles lack flexibility with respect tooptimized overall system or apparatus performance, especially in termsof throughput.

It is an object of the present invention to improve such methods formanufacturing workpieces and respective apparatus with respect to theaddressed disadvantages, thereby maintaining the respective advantages.

To do so the method for manufacturing workpieces, each treated by amultitude of vacuum treatment processes according to the presentinvention, comprises

-   -   providing a vacuum processing station for each of the vacuum        processes;    -   grouping the vacuum processing stations in at least a first        group of such stations which perform, respectively, first vacuum        treatment processes and in a second group of such processing        stations which perform respectively second vacuum treatment        processes.

Clearly, the first and second vacuum treatment processes includerespectively different or equal processes.

-   -   The first group of vacuum processes has, respectively, first        processing time spans which are generically not equal, but may        be equal, at least a part of these time spans may be equal.    -   The second group of vacuum treatment processes has respective        second processing time spans which generically are unequal.        Nevertheless, at least a part of these second processing time        spans may be equal.    -   The first processing time spans are selected to be shorter than        the second processing time spans.    -   Each workpiece is vacuum treated consecutively by each of the        addressed first vacuum processes and transporting the workpieces        is thereby performed simultaneously from respective ones of the        first processing stations to a next one of the first processing        stations.    -   The workpieces are further treated by the second vacuum        processes, whereby transporting the workpieces is performed        individually to and from selected second processing stations.

Thus, and according to the invention the processing steps are subdividedin a first group with shorter processing time spans and a second groupwith longer processing time spans. The former group is operatedaccording to the parallel transport principle as addressed above, thesecond group is operated by the individual transport principle.

In one embodiment of the method according to the present inventiontreating the workpieces by the second vacuum processes comprisessimultaneously treating such workpieces by equal ones of the secondvacuum treatment processes. Thereby, two or more workpieces are vacuumtreated by equal processes which accords with parallel processing ofsuch workpieces.

In a further embodiment of the method according to the invention theworkpieces are transported from the first group of processing stationsto the second group of processing stations or vice versa in vacuum.

Still in a further embodiment the sum of the first processing time spansis selected to be substantially equal to at least one of the secondprocessing time spans. Thereby, the dead processing time is furtherminimized.

In a further embodiment the workpieces being manufactured aresubstrates.

In a further embodiment the workpieces being manufactured aresemiconductor or storage device wafers.

Still in a further embodiment the workpieces as manufactured aresubstrates for photovoltaic applications, thereby especially formanufacturing solar panels.

The vacuum treatment apparatus according to the present invention andwhich provides for utmost processing flexibility, thereby optimizingprocessing cycle time, comprises

-   -   a first group of first vacuum processing stations;    -   a second group of second vacuum processing stations;    -   wherein the first processing stations are served by a first        workpiece transport arrangement which is conceived for        transporting workpieces simultaneously from respective ones of        the first processing stations to next ones of the first        processing stations;    -   the second processing stations being served by a second        workpiece transport arrangement which is conceived for        transporting workpieces individually to and from selected ones        of the second processing stations.

Thereby, the addressed first workpiece transport arrangement establishesespecially sealingly closing the first group of vacuum processingstations whenever the workpieces are transported into respectivetreatment positions in the addressed first vacuum processing stations.

Further, the addressed first workpiece transport arrangement maycomprise receptacles for receiving the workpieces which areexchangeable, thereby may be automatically exchanged during operation ofthe vacuum treatment apparatus. By such receptacles parts of thetransport arrangement which may become exposed to the treatment by thefirst vacuum processing stations and thereby contaminated may easily beexchanged for cleaning.

In one embodiment of the apparatus according to the present inventionthe first processing stations are circularly grouped about a firstcentral vacuum transport station wherein the first workpiece transportarrangement operates. In a further embodiment of the apparatus accordingto the invention, which may be combined with the embodiment as justaddressed above, the second processing stations are circularly groupedabout a second vacuum transport chamber wherein the second workpiecetransport arrangement operates.

In a further embodiment of the apparatus according to the invention,which may also be combined with any of the addressed embodiments, afurther transport arrangement is provided which is conceived fortransporting workpieces from the first group of processing stations tothe second group of vacuum processing stations. In spite of the factthat such further transport arrangement may operate under ambientatmosphere conditions, in a further embodiment the addressed furthertransport arrangement is operating in vacuum.

Still in a further embodiment of the apparatus according to theinvention, the just addressed further transport arrangement is realizedby at least one of the first and of the second workpiece transportarrangements. Thus, handling of the workpieces from one group ofprocessing stations to the other or vice versa may be performed by thefirst transport arrangement or by the second transport arrangement orthe two transport arrangement may cooperate for such handling.

Still in a further embodiment of the apparatus according to theinvention, which may be combined with any of the embodiments addressedabove, at least two of the second vacuum processing stations are equal.

Still in a further embodiment of the apparatus according to theinvention, which again may be combined with any one of the addressedembodiments, the first processing stations are conceived for performingfirst vacuum processes with respective first processing time spans.Thereby, these first processing time spans may generically all bedifferent, whereby at least part of these time spans may also be equal.The second processing stations of this embodiment are conceived forperforming second vacuum processes with respective second processingtime spans. Again generically, these second processing time spans may bedifferent, whereby at least a part of these second processing time spansmay be equal. According to this embodiment the first processing timespans are shorter than the second processing time spans.

In one variant of the just addressed embodiments the sum of the firstprocessing time spans is selected substantially equal to at least one ofthe second processing time spans.

Still in a further embodiment of the apparatus according to theinvention, which may be combined with all embodiment addressed, theworkpieces are wafers, thereby especially wafers for manufacturingsemiconductor devices, storage devices or photovoltaic devices. In afurther embodiment the addressed workpieces are substrates for solarpanels.

The invention shall now be further explained by means of examples andwith the help of figures. The figures show:

FIG. 1 schematically and in top view, a vacuum treatment apparatusaccording to the present invention and residing on rotational transportof workpieces, thereby performing the method for manufacturing accordingto the invention;

FIG. 2 schematically and in a side aberration view, a vacuum treatmentapparatus according to the present invention and residing on linear or“inline” workpiece transportation and performing the method according tothe invention;

FIG. 3 schematically and in a lateral view, a further embodiment of agroup I processing arrangement as may be provided in the embodiment ofthe apparatus and method according to the invention of FIG. 1;

FIG. 4 schematically and in lateral view, a part of a transport table ina further embodiment and as may be provided in each of the embodimentsaccording to FIGS. 1-3;

FIG. 5 in a representation in analogy to that of FIG. 3, a furtherembodiment of the arrangement as of FIG. 3;

FIG. 6 in a representation in analogy to that of FIG. 4, the embodimentof FIG. 4 adapted to be applied and operated in the embodiment as ofFIG. 5;

FIG. 7 in a simplified and schematic top representation, a furtherembodiment of the apparatus according to the present invention andoperating the method according to the invention, and

FIG. 8 in a simplified and schematic top representation in analogy tothat of FIG. 7, a further embodiment of the apparatus according to thepresent invention operating according to the method of the presentinvention.

In FIG. 1 there is schematically shown a vacuum processing apparatusaccording to the present invention to be operated for the methodaccording to the invention. An apparatus 1 according to the presentinvention comprises a multitude of processing stations P₁₁ to P_(1n),P₂₁ to P_(2m). First processing stations P₁₁ to P_(1n) are circularlygrouped about a first vacuum transport chamber 3 ₁, thereby forming afirst group I. Within the first vacuum transport chamber 3 ₁ thereoperates a first transport arrangement 5 ₁. The transport arrangement 5₁ is drivingly rotatable—φ—about a central axis A₁ within vacuumtransport chamber 3 ₁. As an exemplary realization form the transportarrangement 5 ₁ comprises a number of radially extending transport arms7 ₁ being simultaneously drivingly and controllably extendable andretractable in radial direction as schematized by the common radialdrive r. Each transport arm 7 ₁ carries at its end remote from axis A₁ aworkpiece support 9. As was addressed all transport arms 7 ₁ arecontrolled with respect to their extension and retraction by drive r insynchronism. The overall transport arrangement 5 ₁ is rotatable aboutaxis A₁ in a controlled manner and in the direction φ.

Thus, workpieces as schematically shown in dashed line at 11, aresimultaneously gripped by the respective workpiece supports 9 of thetransport arms 7 ₁, are simultaneously retracted from the respectivefirst processing stations P₁₁ to P_(1n). Thereafter, the transportarrangement 5 ₁ is rotated in direction φ to bring the workpieces 11 inalignment with the next processing stations considered in direction φ.There, the workpieces are simultaneously applied to the respective firstprocessing stations P₁₁ to P_(1n) by simultaneously extending thetransport arms 7 ₁. Thus, the first group I of processing stations P₁₁to P_(1n) is served by the first transport arrangement 5 ₁simultaneously, and in a predetermined sequence. Rotation of the firsttransport arrangement 5 ₁ about axis A₁ as well as simultaneousextension and retraction of the transport arms 7 ₁ is time-controlled asschematically shown in FIG. 1 by means of a time controller unit 13 atCONTR. (φ, r).

A second group II of processing stations P₂₁ to P_(2m) is groupedcircularly along a second vacuum transport chamber 3 ₂. The processingstations P₂₁ to P_(2m) of this second group II are served by a secondtransport arrangement 5 ₂ which is drivingly and controllably rotatableabout central axis A₂ of vacuum transport chamber 3 ₂ forth and back inboth directions, as indicated by the double-arrow β. The secondtransport arrangement 5 ₂ comprises one or possibly more than onetransport arms 7 ₂ which may individually be radially extended andretracted as shown by drive R. If more than one transport arms 7 ₂ areprovided, they are controllably extendable and retractable in mutualindependency. The transport arm 7 ₂ comprises a workpiece support 9 ₂ atits end opposite to axis A₂.

Thus, the processing stations P₂₁ to P_(2m) of the second group II areserved by the second transport arrangement 7 ₂ individually inopposition to serving the processing stations P₁₁ to P_(1n) of the firstgroup I by first transport arrangement 5 ₁ which is performedsimultaneously and in a predetermined sequence. Rotational control ofthe second transport arrangement 7 ₂ as well as extension and retractionof its at least one transport arm 7 ₂ is controlled by a time controlunit as e.g. the time control unit 13, as shown by contr. β, R.

Clearly, there is provided at least one input loadlock for workpieces toeither the first group I of processing stations or to the second groupII of processing stations and at least one output loadlock forworkpieces from either the first group I or from the second group II. Aswas addressed, the overall apparatus according to the present inventioncomprises both groups I and II of processing stations. A furthertransport T for workpieces from the first group I of processing stationsto the second group II of processing stations is schematically shown inFIG. 1 by the double-arrow T. Most generically, this further transportarrangement T may operate via respective loadlocks in the vacuumtransport chambers 3 ₁ and 3 ₂ via ambient atmosphere, or may, as shownin dash line at 15, be performed in vacuum. The provision of respectiveinput, output or input/output loadlocks at the respective vacuumtransport chambers 3 ₁ and 3 ₂ is not shown in FIG. 1.

It becomes clear from FIG. 1 that the apparatus according to the presentinvention combines two handling or transport principles, namely in groupI as indicated in FIG. 1, where workpieces are simultaneouslytransported from one to the next processing station and according togroup II according to FIG. 1, where workpieces are individuallytransported towards and from processing stations.

In FIG. 2 this principle is shown in an apparatus according to thepresent invention, which resides on linear workpiece transportation.Processing stations Q₁₁ to Q_(1n) of a first group I of processingstations arranged along a first vacuum transport chamber 19 ₁ are servedby a first transport arrangement 17 ₁ which is controllably anddrivingly linearly movable in one direction as shown by the arrow Lalong the processing stations Q₁₁ to Q_(1n). As most schematically shownin FIG. 2 by drive S the linear conveyor 17 ₁ is controllably movabletowards and from the processing stations Q₁₁ to Q_(1n) so that all theprocessing stations are simultaneously served with workpieces 21. Thus,in perfect analogy to the processing stations of group I in FIG. 1 theprocessing stations Q₁₁ to Q_(1n) of group I of FIG. 2 aresimultaneously served by conveyor arrangement 17 ₁ with workpieces in apredetermined sequence established by conveying direction L.

The second processing stations Q₂₁, Q₂₂ to Q_(2m) linearly arrangedalong second vacuum transport chamber 19 ₂ are served by a secondtransport arrangement 17 ₂ which is linearly movable forth and back in acontrolled driven manner as shown by the double-arrow t and whichcomprises at least one workpiece support 23 which is individuallyliftable and retractable towards and from the processing stations Q₂₁ toQ_(2n) of the second group II as schematically shown by the double-arrowdrive h. Thus, the second group II as of FIG. 2 is served in perfectanalogy with the second group II of FIG. 1. As schematically also shownin FIG. 2 time control of the linear conveyor movements L and 1 as wellas up and down movements of the workpiece holders towards and from therespective processing station is controlled by a time control unit 27.

What was explained with respect to the further transport arrangement Tas well as with respect to input, output and possibly input/outputloadlocks for workpieces to the overall apparatus we refer to therespective explanations in context with the embodiment of FIG. 1 whichare also valid for the linear concept as of FIG. 2.

In both embodiments of the apparatus according to the present inventionand as most schematically shown in the FIGS. 1 and 2 the group I withthe respective transporting of workpieces simultaneously towards andfrom the processing stations P₁₁ to P_(1n) in a predetermined sequenceis exploited for processing stations at which workpiece processing isperformed during respective first processing time spans which areshorter than respective processing time spans as necessitated byprocesses in the processing stations P₂₁ to P_(2m) of group II. The sameis valid with respect to group I and group II according to the linearconcept of FIG. 2. Thereby and if at all possible for a specific overallprocessing of the workpieces the sum of the processing time spans alonggroup I is selected to be at least substantially equal to at least oneprocessing time span of a processing station of group II. Further, twoor more than two of the processing stations of group II are selected tobe equal, so that in group II real parallel processing with equalprocesses is performed.

In FIG. 3 there is schematically shown a further embodiment of the groupI arrangement. In this embodiment the first transport arrangement 105 ₁comprises a transport table 106 which is rotatably drivable about anaxis A₃ by means of a controllable rotation drive 107. Workpieces ase.g. wafers 109 are deposited along the periphery of transport table 106along a circular locus and are held in position by respective holders111 on table 106. A multitude of first processing stations U₁₁-U_(1n) isprovided in a circular arrangement about axis A₃ at the first vacuumtransport chamber 103 ₁ with a radial distance from axis A₃ whichaccords with the radial distance from the addressed axis A₃ with whichthe workpieces 109 are deposited in a circular fashion about axis A₃ ontable 106. By means of a linear up/down drive 113 the transport table106 may controllably be lifted up towards the first processing stationsU₁₁-U_(1n), and respectively retracted therefrom. In operation theworkpieces 109 are loaded via a respective loadlocking arrangement 115with respective transport robots onto the transport table 106. The firstprocessing chambers U₁₁-U_(1n), as was addressed circularly groupedabout axis A₃, and the workpieces 109 circularly grouped as well aboutaxis A₃, are angularly positioned about axis A₃ so that all theworkpieces 109 may simultaneously be brought in alignment withrespective ones of the first processing stations U₁₁-U_(1n) byrespective rotational steps and driven by rotation drive 107.

In operation all the workpieces 109 deposited on the transport table 106are simultaneously brought in alignment, each with one of the processingstations U₁₁-U_(1n) by means of a controlled rotation drive 107. Thenthe transport table 106 is lifted by the linear lifting drive 113 in acontrolled manner up to all the workpieces 109 being positioned withinthe or adjacent to the respective first processing stations in treatmentposition. As schematically shown by the sealing members 117, whenever,by the addressed lifting operation of the transport table 106, theworkpieces 109 are located in treatment positions, there is establishedclosing of at least a part of the first processing stations U₁₁-U_(1n)towards the vacuum transport chamber 103 ₁. Such closing may be ofdesired degree up to establishing vacuum seal. Such closing is furtherestablished by cooperation of the border of the processing stationsU₁₁-U_(1n) as by the sealing members 117 with the area of the transporttable 106 just along and adjacent to the workpieces 109 or bycooperation of the addressed border area of the processing stations withthe workpieces 109 themselves or by respective cooperation of the borderarea of the processing stations with respective holders 111 at thetransport table 106. After the workpieces 109 have been all treated intheir momentarily attributed processing stations U₁₁-U_(1n), by means ofthe linear drive 113 the transport table 106 with the yet treatedworkpieces 109 is retracted, is rotated by means of the rotation drive107 by a predetermined angle so as to bring all the workpieces 109 intoalignment with respectively next processing stations U₁₁-U_(1n).

Thus, by the group I arrangement as shown in FIG. 3 again all workpiecesare simultaneously transported and brought into respective treatmentpositions at respective ones of the first processing stations as wasalready explained in context with the embodiment of FIG. 1 as well aswith the embodiment of FIG. 2.

In one variant of the embodiment as of FIG. 3 and as schematically shownin FIG. 4 the holders 111 as of FIG. 3 are realized by receptacles 119which are removably and replaceably introduced into respective openings121 in transport table 106′. The receptacles 119 are easily removableand re-applicable to the transport table 106′, are e.g. just depositedin the addressed openings 121 for positioning and holding the workpieces109. In this embodiment the addressed closing of the first processingstations U₁₁-U_(1n) towards the vacuum transport chamber 103 ₁ as ofFIG. 3, especially if realized as a vacuum seal, is performed bycooperation of the border or rim area of the first processing stationsU₁₁-U_(1n) as e.g. by means of the sealing members 117 with the borderor rim area of the receptacles 119. At least parts of the overalltransport table 106′ are exposed to the respective treatments in thefirst processing stations U₁₁-U_(1n). Thus, providing receptacles 119 asin the variant of FIG. 4 allows to easily exchange those parts at thetransport table 106′ which are most exposed to the treatment effect bythe addressed processing stations. Thereby, these parts, i.e. thereceptacles 119, may easily be replaced and cleaned outside thetreatment apparatus and may be reapplied instead of cleaning at leastthe addressed areas or parts of the transport table. Thereby,considerable savings are reached with respect to time spans during whichthe overall apparatus is inoperative due to cleaning operations to beperformed.

Especially if a closing or separation of processing atmospheres of thefirst processing stations U₁₁-U_(1n) with respect to the vacuumatmosphere within the vacuum transport chamber 103 ₁ is established bymeans of cooperating surfaces on one hand along the border of theprocessing stations and on the other hand along the border or rim of thereceptacles 119 as was addressed, it becomes possible to ensure suchclosing to be continuously guaranteed by frequent cleaning of thereceptacles 119 without or at least without substantial standstill timespans of the apparatus. Standstill time spans for such cleaningoperations of the addressed areas are practically completely avoided ifthe receptacles 119 are automatically removed from the transport table106′ and are automatically reapplied during ongoing operation of thearrangement, which may be performed, as perfectly known to the skilledartisan, by removing and re-introducing the addressed receptacles 119similarly to workpieces 109 via a respective loadlock arrangement with arespective handling robot and by providing respective magazines forcleaned and yet uncleaned receptacles 119 outside the vacuum transportchamber 103 ₁.

In FIG. 5 there is shown schematically and in a representation inanalogy to that of FIG. 3 a further embodiment of the group Iarrangement. As clear to the skilled artisan having read theexplanations with respect to the embodiments of FIGS. 3 and 4, thedifference of the embodiment according to FIG. 5 to that of FIG. 3 isthat in the FIG. 5 embodiment the transport table 106 is rotatable bythe controlled drive 107, but is not liftable by a linear lifting drive113 as in the embodiment of FIG. 3. Instead, the transport table 106″comprises openings 123 similar to the openings 121 which were explainedin context with FIG. 4. The openings 123 are nevertheless smaller thanthe dimension of the workpieces 109 so that latter may be deposited uponthe addressed openings 123 as schematically shown. Lifting of theworkpieces 109 towards and back from the first processing stationsU₁₁-U_(1n) is performed by respective lifting arrangements 125 which aremounted to the vacuum transport chamber 103 ₁. Each lifting arrangement125 comprises a controlled lifting drive 126 and an elevator member 127which is controllably moved up and down by the controlled lifting drive126. The elevator members 127 respectively are lifted towards theworkpieces 109 through the opening 123 in transport table 106″ and liftthe workpieces 109 into treatment positions within the first processingstations U₁₁-U_(1n).

The lifting drives 126 are operated substantially in synchronism tosubstantially simultaneously lift or retreat the workpieces 109. Byrespective rotation of the transport table 106″ the workpieces 109 arebrought in alignment with the lifting arrangements 125 on one hand andthe respective first processing stations on the other hand.

Especially for the embodiment of FIG. 5 the concept of supporting andtransporting the workpieces by receptacles as was addressed in contextwith FIG. 4 brings up additional advantages. This shall be explainedwith the help of FIG. 6. According to FIG. 6 and in comparison with theembodiment of FIG. 5 the openings 123′ within transport table 106′″ areslightly larger than the dimensions of the respective workpieces. In theopenings 123′ there are respectively applied receptacles 129 as wasexplained in context with FIG. 4 for the receptacles 119. According toFIG. 6 the receptacles 129 comprise, facing the lifting arrangements 125with the elevators 127, guiding members 131 which match with respectivemembers 133 at the top end of the elevators 127. Thus, there isestablished by mutual linear movement an accurate mutual positioning andfixation between the receptacles 129 and the elevators 127 during liftup and retraction of the workpieces 109 towards and from their treatmentpositions within the first processing stations U₁₁-U_(1n) according toFIG. 5.

Clearly and with respect to cleaning as well as closing, i.e. separatingprocessing atmospheres of the first processing stations from the vacuumatmosphere within the transport chamber, the receptacles 129 accordingto the embodiment of FIG. 6 have additionally the same advantages aswere already addressed in context with receptacle 119 of the embodimentof FIG. 4.

The skilled artisan is now aware of the multitude of optimized optionsfor process grouping and respective time control of the overallapparatus comprising the at least two processing groups I and II withtheir respective transport arrangements built up according to the twoaddressed principles.

In FIG. 7 a further embodiment of the apparatus according to the presentinvention operated according to the method according to the invention isshown. The overall apparatus or system 30 again comprises a group Iassembly and a group II assembly as was principally exemplified incontext with FIGS. 1 to 6. Group I assembly comprises first processingstations C₁ to C₅ and an input/output loadlock station C₀. A firsttransport arrangement 32 operates in vacuum transport chamber 33 and isconceived as was already addressed for simultaneously serving theprocessing stations C₁ to C₅ as well as loadlock station C₀. The GroupII comprises the second processing stations C_(4(a)) to C_(4(d)). Inthis specific example the second processing stations C_(4(a)) toC_(4(d)) are identical. The second group II assembly comprises withinvacuum transport chamber 35 the second transport arrangement 37conceived to individually serve the second processing stations C₄. Inthis example the second transport arrangement 37 is further conceived togrip the workpieces from the first transport arrangement 32 and to thusrealize the further transport T as was shown in FIG. 1 operating invacuum. Clearly instead of performing the addressed transition functionfrom group I to group II or vice versa by second transportingarrangement 37, it is also possible to perform this function byrespective conception of the first transport arrangement 32. Still inanother manner of realizing the addressed further transport between thegroups I and II both transport arrangements 32 and 37 may cooperate withrespect to transport movement.

Further, it is absolutely possible to separate the vacuum atmosphere ofvacuum transport chamber 33 from the vacuum atmosphere in vacuumtransport chamber 35 by applying in between a loadlock arrangement fortransiting the workpieces from one group to the other. Further, it isalso possible to provide as was already addressed in context with theFIGS. 1 and 2 a separate transport arrangement to perform transitionfrom group I assembly to group II assembly, thereby additionallyproviding for a buffering station for the workpieces. Further, more thanone group I assembly and/or group II assembly may be combined toestablish a network-like arrangement of processing stations so as tooptimize the overall processing cycle.

In the specific embodiments as shown in FIG. 7 the number of fastprocessings in the stations C₁ to C₅ may be said to be decoupled fromthe significant longer lasting processes at stations C₄, whereby anumber of identical process stations C₄ is applied. Principally, thenumber of slow process stations C₄ is determined optimally by the ratioof overall cycle time in the group I assembly and processing time spanof a process in a C₄ station.

In FIG. 8 there is schematically shown a further embodiment of anapparatus according to the present invention operated according to themethod according to the invention. This embodiment is specificallytailored for manufacturing of heterojunction solar cell panels. In afirst processing station 41 of group I assembly, heating of thesubstrate is performed. After heating the substrate is transported togroup II processing. There parallel processing is performed at threesecond processing stations 43 _(a) to 43 _(c) by depositing a layer ofamorphous hydrogenised silicon. Then the substrates are fed back to thegroup I assembly, where in a first processing station 45 there isdeposited an indium tin oxide layer. Then the substrates are dispatchedto ambient via loadlock station 47. The heating in station 41 as well asthe ITO layer deposition in station 45 may be done within typically 20sec. The deposition of the amorphous hydrogenised silicon requiresapprox. 60 sec. Thus, wafer processing in the group I assembly includingpassing through the loadlock station 47 has a cycle time which issubstantially equal to the processing time span in each of the secondprocessing stations 43 _(a) to 43 _(c). Thereby in fact group Iprocessing may be considered as one overall process which is of equalprocessing time span to each of the processings in the second group IIassembly. Therefore, an overall apparatus is in fact realized whereatworkpiece processing is established in processing steps of equalprocessing time spans, the processing in group I assembly beingconsidered as one processing step.

The invention claimed is:
 1. A vacuum treatment apparatus comprising: afirst group of first vacuum processing stations; a second group ofsecond vacuum processing stations; said first vacuum processing stationsbeing exclusively served by a first workpiece transport arrangementconfigured for transporting workpieces, said first workpiece transportarrangement being movable to position at least two of said workpiecesadjacent at least two different first vacuum processing stations and tosimultaneously transport said workpieces from said at least two firstvacuum processing stations to a next at least two first vacuumprocessing stations; said second vacuum processing stations beingexclusively served by a second workpiece transport arrangementconfigured for transporting workpieces individually to and from selectedones of said second vacuum processing stations.
 2. The apparatus ofclaim 1, wherein said first vacuum processing stations are circularlygrouped about a first central vacuum transport station comprising saidfirst workpiece transport arrangement.
 3. The apparatus according toclaim 1, wherein said second vacuum processing stations are circularlygrouped about a second vacuum transport chamber comprising said secondworkpiece transport arrangement.
 4. The apparatus of claim 1, furthercomprising a further transport arrangement conceived for transportingworkpieces from said first group of first vacuum processing stations tosaid second group of second vacuum processing stations.
 5. The apparatusof claim 4, wherein said further transport arrangement is operating invacuum.
 6. The apparatus of claim 5, wherein said further transportarrangement includes at least one of said first and of said secondworkpiece transport arrangements.
 7. The apparatus according to claim 1,wherein at least two of said second vacuum processing stations areconfigured to perform equal processes.
 8. The apparatus of claim 1,wherein said first vacuum processing stations are conceived forperforming first vacuum processes with a respective first processingtime span, said second vacuum processing stations are conceived forperforming second vacuum processes with a respective second processingtime span, said first processing time spans being shorter than saidsecond processing time spans.
 9. The apparatus of claim 8, wherein thesum of said first processing time spans is substantially equal to atleast one of said second processing time spans.
 10. The apparatus ofclaim 1, wherein said workpieces are wafers.
 11. The apparatus of claim10, wherein said wafers are wafers for manufacturing semiconductordevices, storage devices or photovoltaic devices.
 12. The apparatus ofclaim 1, wherein said workpieces are substrates for solar cell panels.13. The apparatus of claim 1, wherein the first workpiece transportarrangement comprises a plurality of workpiece supports.
 14. A vacuumtreatment apparatus comprising: a first group of first vacuum processingstations; a second group of second vacuum processing stations; saidfirst vacuum processing stations being exclusively served by a firstworkpiece transport arrangement configured for transporting workpieces,said first workpiece transport arrangement being movable to position atleast two of said workpieces adjacent at least two different firstvacuum processing stations and to simultaneously transport saidworkpieces from said at least two first vacuum processing stations to anext at least two first vacuum processing stations; said second vacuumprocessing stations being exclusively served by a second workpiecetransport arrangement configured for transporting workpiecesindividually to and from selected ones of said second vacuum processingstations wherein the first workpiece transport arrangement is at leastone of: a) a transport table rotatably drivable about a central axis andsuitable for receiving workpieces deposited along a periphery thereofand along a circular locus, b) a transport arrangement rotatablydrivable about a central axis and comprising a plurality of radiallyextending arms, and c) a linear conveyor arrangement with workpieces ina predetermined sequence, so as to bring all the workpieces intoalignment with respectively next first vacuum processing stations.